Interchangeable elastic pad for abrading,grinding and sanding machine



Aprll 15, 1969 E. VICHI INTERCHANGEABLE ELASTIC PAID FOR ABRADING,GRINDING AND SANDING MACHINE Sheet of 2 Filed May 25, 1966 ATTORNEYS3,438,154 GRINDING April 15, 1969 E. VICHI INTERCHANGEABLE ELASTIC PADFOR ABRAUING,

AND SANDING MACHINE Sheet Filed May 25, 1966 INVENTOR Ettore V'Lc\-\'\.

aA-VQW 3M8 2 in ATTORNEYS United States Patent US. Cl. 51-135 2 ClaimsABSTRACT OF THE DISCLOSURE An abrasive belt pressurizing backing padconsisting of flexible tubes engaged on the side thereof opposite thebelt by an elastic plate adapted to be bent or curved in the centralarea thereof to thereby provide a greater pressure at the central areaof the abrasive belt than at the edges.

Up to the present time the grinding, abrading or leveling machines areprovided with an abrasive belt which rapidly moves in a straight linewhile being supported by a pad having a rigid plan surface, the elasticsuspension of said pad being obtained by means of spring supports,pneumatic or hydraulic systems.

The abrasive contact surface between the belt and the object to beground or leveled is plane and prevents the dust forming during thegrinding operation from escaping outwards. It follows that the abrasivebelt gets easily clogged up with dust.

As a consequence thereof the clogged belt cannot accomplish its abrasivefunction satisfactorily because the contact with the surface to beground is unequal. The treated surfaces result to be irregular andstreaky.

The present invention relates to an interchangeable pad suited to beapplied to grinding or leveling machines with an abrasive belt forgrinding or leveling surfaces of wood, iron, plastic or any othermaterial as well as painted or non-painted plan or Wavy surfaces,whereby the clogging due to the working residues has to be absolutelyavoided, said pad being characterized by means suited to press theabrasive belt against the surface to be treated but only inpredetermined regions thereof and preferably with more pressure at thecenter of the surface than at the edges, thereby providing the work tobe removed from the interspaces comprised between said regions.

According to a preferred embodiment of the invention the slide glidingface of the pad on the non-abrasive face of the belt is realized by anelastic cloth fixed on the sides of the housing and having rolls ortubes resting thereon. It is obvious that by pressing the pad on thebelt which is fast moving on the surface to be treated, the tubes orrolls will partially give way thereby causing the belt to adhere to thesurface in various contact regions, the number of which depends on thenumber of the tubes or rolls making up the pad. It is also obvious thatby this manner every imperfection of the surfaces to be leveled will beeliminated by the abrasive belt.

Furthermore, and this is the major feature of the invention, the Workdust residues, produced by the abrasive belt, will actually escapethrough the spaces between the various contact points of the pad due tothe provision of the elastic tubes or rolls since the cutting effectedby the abrasive belt is not performed in a plane but on a semicurvedface.

To make the invention better understood some embodiments of the pad willbe described hereinafter by referring to the accompanying drawings, inwhich:

FIG. 1 is a longitudinal view on a pad according to the presentinvention as applied to a grinding or levelling machine.

3,438,154 Patented Apr. 15, 1969 ICC FIG. 2 is a cross section thereof.

FIG. 3 is a perspective view of said pad during its operative phase.

FIG. 4 is a view of the particular form which the elastic clothunderneath the rolls assumes during the working process.

FIG. 5 is a cross section through a second embodiment of the pad of theinvention which is provided with a device suited to apply a largerpressure at the center.

FIG. 6 is the corresponding side view.

FIG. 7 is the corresponding perspective view.

FIG. 8 is a view of a further modification of the embodiment of FIG. 6.

FIG. 9 is the perspective view of the pad shown in FIG. 8. The pad 1shown in the FIGS. 14 is illustrated as resting on the abrasive belt 2which is mounted on the rolls 3, 3. FIG. 2 shows a side view of pad 1,wherein the elastic tubes 4 are mounted within the housing 5 and havethe cloth 6 fixed laterally to housing 5 and tangentially adhering tothe lower surface of said tubes. In FIG. 3, pad 1 is shown as resting onthe nonabrasive face of belt 2 while the object 7 is ready to be groundor leveled by the device of the invention. FIG. 4 illustrates theposition which the elastic cloth 6 will assume when pad 1 is pressed onabrasive belt 2 during the operation and clearly shows the contactpoints 8 provided by the elastic tubes or rolls 4.

The pad of the invention fits to work not only plan surfaces but alsowavy ones since pad 1 provided with elastic tubes assumes the functionof a so-called sensing pad i.e., it conforms to accomplish an operationsimilar to the one obtainable by hand. Depending on the kind of work tobe executed a grinding machine may have inserted therein, any suitablepad provided with the most convenient number of elastic tubes.

Practical experimental tests have shown that the modificationsillustrtated in the FIGS. 59 may considerably increase the efficiency ofthe pad of the invention as well as improve the work done thereby.

The pad illustrated with reference to FIGS. 1-4 has the disadvantage ofwearing 01f the lateral edges of the objects or panels to be treated,especially in cases in which the surface of the structure of said panelsis irregularly finished or formed.

For grinding or smoothing of such irregular surfaces it is required toremove a large amount of material from the entire surface and for thisreason the pressure exerted by the panels on the elastic rolls must bevery large.

At the side edges of the panels, where the pressure zone ends, theelastic rolls obviously bend, thereby lowering the abrasive belt belowthe working plane. It follows that too much material is going to beremoved from the edges of the panels causing a substantial undesirablewear of said panels.

In the modifications shown in the FIGS. 59 the elastic rolls will get acurvature in their longitudinal direction and have their maximum camberat the central part oriented towards the panels to be worked.

Said curvature will absolutely prevent the lateral edges of the panelsfrom getting worn off.

The pad 1 in FIG. 5 is provided with an adjusting device 9 which actsupon an elastic plate 10 so as to have the elastic tubes 4 exert mostsuitable pressure on the panels, that is the largest pressure at thecenter and the smallest pressure at the edges.

By increasing the pressure of the elastic rolls 4 against the center ofthe panel 7 it is possible to expand the working zone with a pressurewhich decreases from the center towards the sides.

The amount of the curvature of the elastic rolls and the pressurethereof against the panel will be selected according to the amount ofmaterial which has to be removed from the surface of the panel in orderto correct the irregularities or deformations thereof in the bestpossible way without wearing off the side edges.

The device 9 is made of a pair of bevel gears 19-21 providing for thebending or deflecting of the plate 10 placed below and hence the bendingof the elastic rolls 4 constituting the pad of the invention. The driveis imparted by the handle 13 and the shaft 20.

In FIG. 6 the dash line indicates the curvature assumed by the plate 10in order to exert a larger pressure at the center than at the sides,said pressure being transmitted to the rotating abrasive belt 2, while18 indicates the frame.

In the modification of FIG. 8 an adjustable cross brace 11 is placed atthe center of the flexible plate 10 to constrain the center of curvatureof said plate while the ends of same have devices 9'9" applied theretoto provide for a larger or smaller bending of the plate.

In other words, the plate is fixed at the center while the edges of samemay be lifted by means of said devices 9' and 9".

At any rate, the system for bending the plate 10 may be of any suitabletype and the two above mentioned solutions may be combined, if sodesired.

The flexible tubes or rolls may have closed ends and may be filled witha pressure fluid and so work as a kind of pneumatic tubes, withouttherefore departing from the spirit of the present invention.

What is claimed is:

1. An interchangeable pad to be applied to grinding and levellingmachines with an abrasive belt for levelling and smoothing surfaces ofwood, iron, plastic and the like material, as Well as painted andunpainted plane and wavy surfaces, said surfaces having a center zoneand having edges, said belt having one non-abrasive face, said padeliminating any danger that the work residues clog said abrasive belt,comprising means for pressing said abrasive belt against said surface tobe worked at predetermined zones and preferably with a pressure largerat said surface center than at said edges, whereby said work residuesmay escape from the interstices between said pressure zones, said meanscomprising a series of elastic rolls of substantially round crosssection; an elastic cloth pressed at said abrasive belt, and at leastone elastic plate pressing on top of said elastic rolls, said platesbeing adapted to be bent or curved in the central area thereof.

2. The pad as claimed in claim 1, said elastic rolls being mounted inthe pad housing tangentially arranged to said elastic cloth, saidnon-abrasive face of said belt adhering thereto.

References Cited UNITED STATES PATENTS LESTER M. SWINGLE, PrimaryExaminelr. D. G. KELLY, Assistant Examiner.

